Post and Care

Usually, when you get a toothache, it is because the tooth is badly decayed or very heavily restored (filled).  When a toothache is bad enough, the nerve inside it is dead or dying, and in order to relieve the toothache or abscess, it is necessary to either extract the tooth, or to remove the nerve from the tooth.  The latter choice saves the tooth, and the procedure is called a root canal.  When a root canal has been performed on a tooth, we say that the tooth has been "endodonticly treated".  Endodonticly treated teeth have a number of  characteristics that makes them different than normal "vital" teeth (teeth with live nerves inside them). 

Endodonticly treated teeth tend to be badly damaged above the gumline due to decay and old fillings.  They also are more brittle than vital teeth, something like a dead tree branch in comparison to one that is alive.  For these reasons, once the root canal has been performed, these teeth need special treatment, or they tend to break a few years down the line.  This is especially true of back teeth that have broad biting surfaces.  They are likely to shear off because of biting forces.  For this reason, simple fillings do not usually restore them for very long.  These teeth need to have crowns placed in order to protect the investment in the root canal treatment.  

But unfortunately, because of the very poor condition these teeth have been left in as a result of the original decay, there is often not very much tooth left above the gumline to "hang" the crown on.  For this reason, we need to do a special kind of filling on the tooth that will be so firmly embedded in what does remain of the tooth that it will not dislodge later when it is prepared as a core for the crown.  (A core is that part of the tooth and the fillings in it that are left over after the tooth has been prepared to receive a crown.)  

The first step is to remove some of the gutta percha that was used to seal one or more of the root canals in the tooth.  Then, using a series of graduated rasps, the inside of the canals are enlarged and shaped to receive a specially made metal "post" that exactly fits the hole made by the last rasp.  These posts are usually pre-manufactured and come in many different shapes.  The post is then cemented in the hole so that it is firmly embedded in the root of the tooth, and projects up above the level of the gums in order to help retain a filling that will be placed over it.